title: In situ grafting silica nanoparticles reinforced nanocomposite hydrogels.
abstract: Highly flexible nanocomposite hydrogels were prepared by using silica nanoparticles (SNPs) as fillers and multi-functional cross-links to graft hydrophilic poly(acrylic acid) (PAA) by free radical polymerization from an aqueous solution. The SNPs were collected by neighboring polymer chains and dispersed uniformly within a PAA matrix. The mechanical properties of the nanocomposite hydrogels were tailored by the concentration of SNPs according to the percolation model. It was proposed that covalent bonds of adsorbed chains on the filler surface resulted in the formation of a shell of an immobilized glassy layer and trapped entanglements, where the glassy polymer layer greatly enhanced the elastic modulus and the release of trapped entanglements at deformation contributed to the viscoelastic properties.
authors.affiliation: College of Materials Science and Technology, Beijing Forestry University, Beijing, China. yangjun11@bjfu.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.forename: Chun-Rui
authors.initials: CR
authors.lastname: Han
authors.forename: Jiu-Fang
authors.initials: JF
authors.lastname: Duan
authors.forename: Feng
authors.initials: F
authors.lastname: Xu
authors.forename: Run-Cang
authors.initials: RC
authors.lastname: Sun
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D055119:Elastic Modulus; D005609:Free Radicals / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D053758:Nanoparticles / Q000737:chemistry*; D058105:Polymerization; D012822:Silicon Dioxide / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D005609:Free Radicals; D020100:Hydrogels; D014867:Water; C006903:carbopol 940; D012822:Silicon Dioxide